The Catechism of the Catholic Church:
2197 The fourth commandment opens the second table of the Decalogue. It shows us the order of charity. God has willed that, after him, we should honor our parents to whom we owe life and who have handed on to us the knowledge of God. We are obliged to honor and respect all those whom God, for our good, has vested with his authority.
2198 This commandment is expressed in positive terms of duties to be fulfilled. It introduces the subsequent commandments which are concerned with particular respect for life, marriage, earthly goods, and speech. It constitutes one of the foundations of the social doctrine of the Church.
2199 The fourth commandment is addressed expressly to children in their relationship to their father and mother, because this relationship is the most universal. It likewise concerns the ties of kinship between members of the extended family. It requires honor, affection, and gratitude toward elders and ancestors. Finally, it extends to the duties of pupils to teachers, employees to employers, subordinates to leaders, citizens to their country, and to those who administer or govern it. This commandment includes and presupposes the duties of parents, instructors, teachers, leaders, magistrates, those who govern, all who exercise authority over others or over a community of persons.
2200 Observing the fourth commandment brings its reward: "Honor your father and your mother, that your days may be long in the land which the LORD your God gives you."8 Respecting this commandment provides, along with spiritual fruits, temporal fruits of peace and prosperity. Conversely, failure to observe it brings great harm to communities and to individuals.
The duties of children
2214 The divine fatherhood is the source of human fatherhood;16 this is the foundation of the honor owed to parents. the respect of children, whether minors or adults, for their father and mother17 is nourished by the natural affection born of the bond uniting them. It is required by God’s commandment.18
2215 Respect for parents (filial piety) derives from gratitude toward those who, by the gift of life, their love and their work, have brought their children into the world and enabled them to grow in stature, wisdom, and grace. "With all your heart honor your father, and do not forget the birth pangs of your mother. Remember that through your parents you were born; what can you give back to them that equals their gift to you?"19
2216 Filial respect is shown by true docility and obedience. "My son, keep your father’s commandment, and forsake not your mother’s teaching… When you walk, they will lead you; when you lie down, they will watch over you; and when you awake, they will talk with you."20 "A wise son hears his father’s instruction, but a scoffer does not listen to rebuke."21
2217 As long as a child lives at home with his parents, the child should obey his parents in all that they ask of him when it is for his good or that of the family. "Children, obey your parents in everything, for this pleases the Lord."22 Children should also obey the reasonable directions of their teachers and all to whom their parents have entrusted them. But if a child is convinced in conscience that it would be morally wrong to obey a particular order, he must not do so.
As they grow up, children should continue to respect their parents. They should anticipate their wishes, willingly seek their advice, and accept their just admonitions. Obedience toward parents ceases with the emancipation of the children; not so respect, which is always owed to them. This respect has its roots in the fear of God, one of the gifts of the Holy Spirit.
2218 The fourth commandment reminds grown children of their responsibilities toward their parents. As much as they can, they must give them material and moral support in old age and in times of illness, loneliness, or distress. Jesus recalls this duty of gratitude.23
For the Lord honored the father above the children, and he confirmed the right of the mother over her sons. Whoever honors his father atones for sins, and whoever glorifies his mother is like one who lays up treasure. Whoever honors his father will be gladdened by his own children, and when he prays he will be heard. Whoever glorifies his father will have long life, and whoever obeys the Lord will refresh his mother.24
O son, help your father in his old age, and do not grieve him as long as he lives; even if he is lacking in understanding, show forbearance; in all your strength do not despise him… Whoever forsakes his father is like a blasphemer, and whoever angers his mother is cursed by the Lord.25
2219 Filial respect promotes harmony in all of family life; it also concerns relationships between brothers and sisters. Respect toward parents fills the home with light and warmth. "Grandchildren are the crown of the aged."26 "With all humility and meekness, with patience, [support] one another in charity."27
2220 For Christians a special gratitude is due to those from whom they have received the gift of faith, the grace of Baptism, and life in the Church. These may include parents, grandparents, other members of the family, pastors, catechists, and other teachers or friends. "I am reminded of your sincere faith, a faith that dwelt first in your grandmother Lois and your mother Eunice and now, I am sure, dwells in you."28